Tell us your notebook model if necessary, but if you're running Win7 and haven't tried it already, check your microphone recording volume and boost settings as below.
Right-click the speaker icon on your taskbar and choose recording devices to see the Sound window on the left and click on the properties button to see more settings as in the right window.

You can also use the built-in Win7 Sound Recorder program (under All programs/Accessories) to test your microphone (try tapping on it if necessary and adjust the volume and boost settings).

Hope this helps.